2008 aveo problem with cold start, revs funny, surges, or stalls

Hello all, I'm new to the aveo forum and the chevy world. I purchased my 2008 aveo sedan LS (automatic) just two weeks ago, and I'm already having issues with cold starts. Perhaps cold starts isn't the right word, even on a warm day like today the car revved quite hard on initial startup, almost like a surging type of rev after it hadn't been started for approx 24hrs. Tonight after work, the temperature outside was much lower, a chilly night, and the car actually stalled on the first start up attempt. It did however start secondtry and ran perfect like it always does after it's going for about 10 seconds though. I have noticed it sounded weird on cold start since I bought it, but today was the definite indication that something is wrong.

I've read around that the coolant sensor has been a cause of this problem for this particular model of car. However, my air intake hose (from the air filter to the throttle body) is cracked and currently just patched with tinfoil, duct tape, and heavy duty zip ties. Suspecting that this hose might be causing the problems I took it apart today to look at, and found a bit of greasy/oily goop directly below the vacuum hose to the engine (i think that's what it is at least). I'm not sure if this oily goop is normal. Other than that though the hose actually appeared to be quite clean and the air filter was also in good shape. I wanted to probe further into the throttle body, but figured I better not with my limited mechanic skills and no repair manual.

At worst, even if i cant fix the car myself, it'd be nice to sound like I know what im talking about if i have to take it to a mechanic. I appreciate any replies or suggestions to the source of my problem!

edit: a little more info, the car has 111km and the fuel pump can be heard when the key is turned to the on position. Also, to clarify, the car starts immediately when I turn the key (doesn't just turn over with delayed start). Engine light is not on

I would get yourself a can of aerosol carb cleaner. With that rubber tube going to the throttle body removed, spray it into the throttle body while the engine is running. That will clean out your idle air control valve if it is gummed up. That goopy material may have gotten in there and its sticking.

The car slowly continues to get worse... Tonight after work (sat for about 5 hours) it stalled on first start up, then took 2-3 tries of turning the engine over for it to fire at all. My stepfather is going to help me look at it later today sometime, I'll mention probing further into the throttle body to see if we can find and grime. Could a dying battery be the cause? I've noticed a couple piles of white residue where my battery is mounted on the top, and the battery itself looks pretty old. I'll update on here tomorrow if we make any progress.

Quote:

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Originally Posted by JGould

However, my air intake hose (from the air filter to the throttle body) is cracked and currently just patched with tinfoil, duct tape, and heavy duty zip ties. Suspecting that this hose might be causing the problems I took it apart today to look at, and found a bit of greasy/oily goop directly below the vacuum hose to the engine (i think that's what it is at least). I'm not sure if this oily goop is normal. Other than that though the hose actually appeared to be quite clean and the air filter was also in good shape.

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The first thing to do is replace that large air intake hose. If there are any cracks in it at all, that will cause your car to run erratically.

It's important. Don't just patch it, replace it. ;)

Absolutely, I've got one lined up at a junk yard an hour out of town, just need to get there now

I just picked up the hose, couldn't get it from the junkyard so I had to pick it up new for $80 (ouch). I'll be replacing it tomorrow and attempting to clean the throttle body with the aerosol cleaner like Daox recommended. I'll update how it goes then, maybe with some pictures.

In the mean time, I need to ask you guys what a normal 'cold' start sounds like... During a good start, my aveo revs to about 1600RPM upon starting for about 5-7 seconds before relaxing back to about 8-900 (I think this part is normal for cold starting)... but theres a bit of surging or revving noise during the same time. Oddly, the engine RPM's do not change on my dish indicator. Is this normal for aveos?

Quote:

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Originally Posted by JGould

I just picked up the hose, couldn't get it from the junkyard so I had to pick it up new for $80 (ouch). I'll be replacing it tomorrow and attempting to clean the throttle body with the aerosol cleaner like Daox recommended. I'll update how it goes then, maybe with some pictures.

In the mean time, I need to ask you guys what a normal 'cold' start sounds like... During a good start, my aveo revs to about 1600RPM upon starting for about 5-7 seconds before relaxing back to about 8-900 (I think this part is normal for cold starting)... but theres a bit of surging or revving noise during the same time. Oddly, the engine RPM's do not change on my dish indicator. Is this normal for aveos?

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1600 seems high. I have a different engine but my cold start is about 1100-1250

Quote:

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Originally Posted by Pickles

1600 seems high. I have a different engine but my cold start is about 1100-1250

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my cold starts are around 2000, and my hot starts are around the 1650-1700 range. after it runs for a second or two, it settles into the normal 700-900 RPM Idle speed. (and my car has the Ecotec engine.) i just pass off the RPM spike on startup as a part of the ScootaDrive's small but high strung nature.

could and hot start rpm are "directly" related to temperature..

After running some gasline antifreeze to a full tank of gas and spraying the injectors down with cleaner the car has yet to fail to start since. However there still seems to be the mystery revs when starting the car which doesn't sound healthy at all. Plans are to inspect and replace the plugs next. Ill update here if I find anything new. Thanks to everyone for the suggestions and ideas